In minimally-invasive surgery, the identification of anatomical structures must be done through knowledge of the anatomy and knowledge of anatomical landmarks, given the lack of true tactile feedback for the surgeon. When operating in the lower abdomen and pelvis, surgeons of many specialties (e.g., general surgery, colorectal surgery, transplant surgery, urology, obstetrics, gynecology, etc.) are acutely aware of the need for accurate identification of the ureter in order to prevent potentially catastrophic injury to the ureter. Although identification of the ureter may appear to be a simple and routine visual task, difficulties lie in “hostile” abdomens where there have been prior surgeries, inflammation and/or scarring, or if tissue planes are not well defined.
It has been reported that the incidence of ureteral injuries in gynecological procedures is upwards of 3.2%, with 70% of the ureteral injuries not being discovered until after completion of the procedure.
A ureteral injury can result in significant morbidity to the patient. In addition, a ureteral injury can also lead to longer operating room (OR) times (due to the need for ureteral repairs), the involvement of specialists, the potential need for long term ureteral stent placements, and long term effects (such as scarring) that may lead to kidney damage. All of these are costly, both to the patient as well as the hospital, inasmuch as medical insurance generally does not cover costs related to complications from an operation.
Several different approaches are currently used to identify the ureter during a minimally-invasive procedure.
Where the ureter is easily identified visually, the surgeon generally confirms ureter identification by lightly compressing the ureter with an instrument (e.g., graspers, forceps, etc.) and observing the resulting visible contractions of the ureter up and down its length as a response to the instrument stimulus. However, as noted above, the ureter is frequently difficult to identify visually and, even where it is relatively easily identifiable, the ureter does not always generate visually-detectable contractions as a result of an instrument stimulus. Furthermore, care must be taken with this approach to avoid injuring to the ureter.
For these reasons, surgeons have turned to the pre-operative (but post-anesthesia) placement of ureteral stents via cystoscopy. Where the surgery is an “open” procedure, the surgeon can detect the ureteral stent by manual sensation. Where the surgery is a “closed” procedure (e.g., a minimally-invasive procedure), light-emitting stents may be utilized, with the light-emitting stents being detected visually during the minimally-invasive procedure.
However, with ureteral stents, a urologist must generally be available to deploy the ureteral stents up each ureter from the bladder. This process may be time-consuming, which leads to a longer OR time (and thus longer anesthesia time) and comes with its own risks of ureter injury and infection, due to the need to place a foreign object in the ureter. Furthermore, the average cost of the ureteral stent placement procedure is approximately $1500, with studies demonstrating a significant decrease (e.g., up to 85%) in procedural profit margin where prophylactic ureteral stenting is utilized. In addition, even where a ureteral stent is used, ureter injury can still occur. Many experienced surgeons have noted that, at times, the ureteral stent only serves to notify them that they have injured the ureter, i.e., when the surgeons see the ureteral stent exposed inside the abdomen.
Even with these drawbacks, pre-operative ureteral stent placement is quickly becoming routine in hospitals nationwide due to the need to reliably identify the ureter during surgery.
Thus there is a need for a new method and apparatus for reliably identifying the ureter in both open and closed procedures and which eliminates the need for pre-operative ureteral stent placement, whereby to avoid the risks and costs associated with pre-operative ureteral stent placement.